1. Field of the Invention
The present invention, in general, relates to vehicle cargo covers and, more particularly, to flexible vehicle cargo covers placed over the bed of a pickup truck.
Flexible types of covers for pickup trucks are known and are presently referred to, generally, as tonneau types of pickup bed covers. However fastening such types of covers to the bed of the vehicle has heretofore proven difficult to achieve, especially when a portion of the load that is placed inside the pickup be extends higher than the top of the bed of the pickup truck.
Existing tonneau covers do not accommodate very large loads because such kinds of covers fasten to snaps or hooks placed along the perimeter of the bed of the pickup truck. An very large load stretches such kinds of covers to the point where they simply cannot reach the fasteners that are fixedly attached to the exterior of the bed of the vehicle.
Also many pickup truck owners do not desire to deface the appearance of their pickup truck by attaching snap fasteners or hooks to the exterior of their pickup truck bed.
Furthermore, when tonneau covers are normally tightened "hot spots" arise whereby the material which comprises the cover is placed under disproportionate strain. Hot spots are caused by the excessive force necessary to stretch the cover over the bed of the pickup in order to reach the attached fasteners. The greatest strain to the cover is experienced in proximity to each fastener that is used. It is in this area where existing types of tonneau covers are most likely to fail.
This problem is further aggravated when the cover must be stretched over a portion of a slightly oversized cargo item. In this instance the cover can be stretched enough to reach the attached fasteners but in order to do so a significant strain is applied to the cover which tends to considerably shorten its useful life.
Also because of the need to align existing tonneau covers so that their position corresponds exactly with fixedly attached fasteners, present covers tend to be difficult and time consuming to attach and to remove.
Accordingly there exists today a need for a flexible vehicle cargo cover that can easily be placed over the bed of a pickup truck that does not require the use of snaps, hooks, or other fasteners that are permanently attached to the exterior of the bed of the vehicle and which can accommodate cargo items that extend above the top of the bed of the pickup truck and which equalize the tightening forces that are applied about the perimeter of the cover.
2. Description of Prior Art
Cargo covers are, in general, known. For example, the following patents describe various types of these devices:
U.S. Pat. No. 4,823,707 to Salsbury et al, Apr. 25, 1989;
U.S. Pat. No. 4,848,824 to Smith et al, Jul. 18, 1989;
U.S. Pat. No. 4,877,283 to Little et al, Oct. 31, 1989;
U.S. Pat. No. 4,900,204 to Summers, Feb. 13, 1990;
U.S. Pat. No. 4,979,776 to Schwickert, Dec. 25, 1990;
U.S. Pat. No. 5,040,934 to Ross, Aug. 20, 1991;
U.S. Pat. No. 5,050,924 to Hansen, Sep. 24, 1991; and
U.S. Pat. No. 5,165,750 to Pirhonen, Nov. 24, 1992.
While the structural arrangements of the above described devices, at first appearance, have similarities with the present invention, they differ in material respects. These differences, which will be described in more detail hereinafter, are essential for the effective use of the invention and which admit of the advantages that are not available with the prior devices.